Optical Thin Film Design

Description

Thin-film coatings are universal on optical components such as displays, lenses, mirrors, cameras, and windows and serve a variety of functions such as antireflection, high reflection, and spectral filtering. Designs can be as simple as a single-layer dielectric for antireflection effects or very complex with hundreds of layers for producing elaborate spectral filtering effects. Starting from basic principles of electromagnetics, design techniques are progressively introduced toward more intricate optical filter designs, numerical optimization techniques, and production methods, as well as emerging areas such as phase change materials and metal film optics. Worked examples, Python computer codes, and instructor problem sets are included. Key Features: Starting from the basic principles of electromagnetics, topics are built in a pedagogic manner toward intricate filter designs, numerical optimization and production methods. Discusses thin-film applications and design from simple single-layer effects to complex several-hundred-layer spectral filtering. Includes modern topics such as phase change materials and metal film optics. Includes worked examples, problem sets, and numerical examples with Python codes. Cover Half Title Title Page Copyright Page Table of Contents Preface Author Chapter 1 Fundamental Concepts 1.1 Optical Thin Films 1.1.1 Antireflection 1.1.2 High Reflection 1.1.3 Optical Filters 1.1.4 Optical Filters with Metal Films 1.2 Electromagnetic Wave Equation 1.3 Plane Waves 1.4 Power Flux 1.5 Electromagnetic Waves Across Dielectric Boundaries 1.5.1 Derivation of the Boundary Conditions 1.5.2 Normal Incidence 1.5.3 Oblique Incidence 1.5.3.1 TE Incidence 1.5.3.2 TM Incidence 1.6 Problems Further Reading Chapter 2 Optical Thin Film Materials 2.1 Properties of Optical Thin Film Materials 2.2 Dielectric Thin Film Materials 2.2.1 Oxides 2.2.1.1 SiO2 2.2.1.2 TiO2 2.2.1.3 Al2O3 2.2.1.4 Ta2O5 2.2.1.5 SiO 2.2.1.6 Nb2O5 2.2.1.7 Other Oxide Films 2.2.2 Fluorides 2.2.2.1 MgF2 2.2.2.2 CaF2 2.2.3 Nitrides 2.2.3.1 Si3N4 2.2.3.2 TiN 2.2.4 Sulfides 2.2.4.1 ZnS 2.3 Semiconductors 2.3.1 Si 2.3.2 Ge 2.3.3 CdS 2.4 Metals 2.4.1 Ag 2.4.2 Al 2.4.3 Au 2.4.4 Cu 2.4.5 Cr 2.5 Problems References Chapter 3 Single-Layer Antireflection Theory 3.1 Reflection from a Single Dielectric Interface 3.2 Single-Film Antireflection 3.3 Complex Effective Reflectance Index Contours 3.4 Limitations of the Effective Reflectance Index 3.5 Quality Factor 3.6 Normalized Frequency 3.7 Problems Chapter 4 Transfer Matrix Method 4.1 Transfer Matrix Method for Normal Incidence 4.2 Including the Effects of Reflection from the Backside of the Substrate 4.3 Example – Antireflection on Silica Glass 4.4 Film Stacks on Both Sides of the Substrate 4.5 Materials with Complex and Dispersive Refractive Indices 4.6 Calculation of Absorption in Films 4.7 Calculation of the Field Distribution 4.7.1 Example – Field Distribution in the Single-Layer Antireflection Structure 4.8 Oblique Incidence – TE (Transverse Electric) 4.9 Oblique Incidence – TM (Transverse Magnetic) 4.10 Problems References Chapter 5 Multilayer Antireflection Theory 5.1 Two-Layer Quarter-Wave Antireflection Designs 5.2 Two-Layer Non-Quarter-Wave Antireflection Designs 5.3 Three-Layer Antireflection Design 5.4 Principles of the Three-Layer Design Using the Absentee Layer 5.5 Double-V Designs 5.6 Antireflection on a Substrate That Already Contains Thin Films 5.7 Structured and Gradient-Index Films 5.8 Problems References Chapter 6 High-Reflection Designs 6.1 Effective Reflectance Index of a Periodic Layer 6.2 Symmetric Unit Cell 6.3 High-Reflection Designs with Symmetric Unit Cells 6.4 Broadband Reflectors Chapter 7 Herpin Equivalence Principle 7.1 Basic Principles 7.2 Preview Example 7.3 Trilayer Unit Cell 7.4 Trilayer Unit Cell with d2 = 2d1 7.5 (H/2 L H/2) VS (L/2 H L/2) 7.6 Effective Reflectance Index Contour 7.7 Reflection and Transmission at the Reference Wavelength 7.7.1 Stop Band 7.8 Reflection at the Edges of the Stop Band 7.8.1 Higher-Order Absentee Conditions 7.9 Example – Continued from Section 7.2 7.10 Problems Further Reading Chapter 8 Edge Filters 8.1 Basic Concepts 8.2 Equivalent Index of the Passband of a Periodic Stack 8.3 Transition Characteristics 8.4 Numerical Optimization 8.5 Effects of Material Dispersion 8.6 Design Example of a Mid-Infrared Long-Pass Edge Filter 8.7 Problems References Chapter 9 Line-Pass Filters 9.1 Single-Cavity Design 9.1.1 Resonant-Cavity Enhancement 9.2 VCSELs 9.3 Coupled-Cavity Design 9.4 Problems References Chapter 10 Bandpass Filters 10.1 Bandpass Filters by Combining Two Edge Filters 10.2 Coupled-Cavity Bandpass Filters 10.3 Problems Further Reading Chapter 11 Thin-Film Designs for Oblique Incidence 11.1 Angle of Incidence on the Spectral Performance of a Filter 11.2 Continuity Equations and Angle of Incidence (TE) 11.3 Reflection from a Single Interface for TE Polarization 11.4 Behavior of n[sup(z)] with Incident Angle 11.5 Single-Layer Antireflection for TE Incidence 11.6 Continuity Equations and Angle of Incidence (TM) 11.7 Reflection from a Single Interface for TM Polarization 11.8 Behavior of n[sup(z1)] with Incident Angle 11.9 Single-Layer Antireflection for TM Incidence 11.10 Effective Reflectance Index Contours 11.11 Oblique Incidence on a Filter Designed for Normal Incidence 11.12 Multilayer Filters Designed for Oblique Incidence 11.13 A Common Misconception 11.14 Thin-Film Polarizing Beam Splitter 11.15 Problems References Chapter 12 Metal Film Optics 12.1 Optical Properties of Metals 12.2 Transparency of Metals 12.3 Antireflection Designs for Metal Substrates 12.3.1 Using Films with Complex Refractive Indices 12.3.2 Using Films with Real Refractive Indices 12.3.3 Antireflection Using Metal–Insulator–Metal Structures 12.4 Antireflection on Semiconductors 12.5 Bandpass Filters Using Metal Films 12.5.1 Single-Cavity Metal–Dielectric–Metal Bandpass Filter 12.5.1.1 Optical Dispersion of Metals 12.5.1.2 Metal–Dielectric–Metal Cavity Structure Layer Thicknesses 12.5.2 Coupled-Cavity Metal–Dielectric Bandpass Design 12.6 Problems Further Reading Chapter 13 Thin-Film Designs Using Phase Change Materials 13.1 Introduction 13.2 Vanadium Dioxide (VO[sub(2)]) 13.2.1 Optical Properties of Vanadium Dioxide 13.2.2 Antireflection 13.2.3 Resonant-Cavity Structures with a Complex Film at the Center 13.2.4 Resonant-Cavity Structures with VO[sub(2)] at the Center 13.3 Ge[sub(2)]Sb[sub(2)]Te[sub(5)] (GST) 13.3.1 Optical Properties of GST 13.3.2 Antireflection 13.3.3 Resonant-Cavity Structures with GST 13.3.4 Multilayer Designs Using GST Further Reading Chapter 14 Deposition Methods 14.1 Introduction 14.1.1 Optical Thin-Film Design vs Process Design 14.1.2 Major Categories of Deposition Techniques 14.2 PVD 14.2.1 Sputter Deposition 14.2.1.1 DC Sputter Deposition 14.2.1.2 RF Sputter Deposition 14.2.1.3 Reactive Sputter Deposition 14.2.1.4 Ion Beam Sputtering 14.2.2 PLD 14.2.2.1 Sputter Configurations 14.2.3 Thermal Evaporation 14.2.3.1 Resistively Heated Thermal Evaporation 14.2.3.2 Flash Evaporation 14.2.3.3 Electron-Beam-Heated Thermal Evaporation 14.2.3.4 Reactive Evaporation 14.2.3.5 Ion-Assisted Deposition 14.3 Chemical Vapor Deposition 14.3.1 LPCVD 14.3.2 PECVD 14.3.3 ALD 14.4 Thickness Monitoring and Control 14.4.1 Quartz Crystal Microbalance 14.4.2 Optical Monitoring 14.5 Thin-Film Stress Further Reading Chapter 15 Python Computer Code 15.1 Plane Wave Transfer Matrix Method 15.1.1 Subroutine: tmm.py 15.1.2 TMM Reflection Spectrum with and without Substrate Backside (Figure 4.4 in Chapter 4) 15.1.3 TMM Reflection Spectrum Including Complex and Dispersive Materials (Figure 4.5 in Chapter 4) 15.1.4 Subroutine: tmm_field.py 15.1.5 Field Profile inside Single-Layer Antireflection (Figure 4.6 in Chapter 4) 15.1.6 Coupled-Cavity Line Filter (Figure 9.14 in Chapter 9) 15.2 Effective Reflectance Index Contours 15.2.1 Subroutine: contour.py 15.2.2 Single Quarter-Wave Contour (Figure 3.3 in Chapter 3) 15.2.3 Two Quarter-Wave Contours (Figure 5.1 in Chapter 5) 15.2.4 Subroutine: two_contour_equations.py 15.2.5 Intersection between Two Contours (Figure 5.4a in Chapter 5) 15.2.6 Subroutine: vvequations.py 15.2.7 Roots of the Double-V Design (Figure 5.19a) 15.2.8 Subroutine: complex_ns_equations.py 15.2.9 Solving for the Antireflection Condition with an Existing Film (Figure 5.21) 15.2.10 Solving for the Metal and Dielectric Thicknesses in a Metal–Insulator–Metal (MIM) Structure (Figure 12.18) Index